Many techniques have been proposed to protect financial instruments, such as checks and money orders, from nefarious tampering, such as for example fraudulently raising the amount of the instrument. Safety papers have been developed which have chemically reactive coatings that can change color or bleach out a color and reveal a warning word, such as "VOID", thereby showing that an attempt has been made to alter the instrument. Printing techniques have also been used on the back of documents using an ordered large repeating pattern, any change in which should be quickly detected by the human eye.
Several patents disclose various methods for providing secure financial instruments. For example, Todd, U.S. Pat. No. 1,564,724, discloses a commercial paper having solid, positive numerical characters which document are printed with a field of words. Preferably, the field of words for each numerical figure is formed by printing a repetition of groups of letters spelling the corresponding figure word, so that the field is different for each numerical figure. The figures of Todd are preferably limited or terminated by other characters or words for the purpose of preventing the changing of the inscription by adding or inserting other figures.
Angell, U.S. Pat. No. 939,399, discloses a method of protecting commercial paper which utilizes a die set to form figures by cutting into or indenting paper in an area surrounding a numeral or letter, while leaving the area corresponding to the numeral or letter untouched. The surrounding, die impressed areas are constructed so that their exterior outlines are varied. This variation in the exterior outlines and the spacing between figures cooperates so that clear or blank portions of the paper intervene between adjacent figures.
Tonges et al, U.S. Pat. No. 4,175,774, discloses a document having a printed background which, upon copying by a photocopy machine, produces a document which can be readily distinguished from the original. To achieve this feature, the background of the Tonges document is printed with a set of larger dots and a set of smaller dots. The larger dots are of a size which can be reproduced by a copying machine. The smaller dots are of a size that the copying machine cannot reproduce.
Also of interest is French Brevet D'Invention No. 692,505.
Although not relating to methods for protecting the amount figure of a security instrument, several other patents disclose subject matter of interest. For example, Lee, U.S. Pat. No. 4,234,214, discloses a combination of alphanumeric characters for use in forming a serial number of a bank note. An ink jet printer is used to form a multi-colored or patterned field which defines a negative alphanumeric character. Burros, U.S. Pat. No. 3,112,151, relates to a method for correcting mistakes in magnetically encoded characters, such as the magnetically readable characters typically found on the bottom portion of a check. Baker, U.S. Pat. No. 3,983,814, relates to a front of alphanumeric characters which are believed to be more easily readable than conventional characters.
Notwithstanding the above described efforts to make financial instruments more secure, techniques still exist for altering checks and money orders. In order to frustrate financial instrument protection techniques, such as those discussed above, persons interested in altering an instrument have developed a cut and paste scheme. In the cut and paste method of alteration, a person obtains two instruments. One instruments may be for $9.00 and the second for $100.00. Using a scalpel the person carefully removes the 9 from the first instrument and the 1 from the second. The 9 is then pasted into the area where the 1 had been removed, thereby fraudulently raising the amount of the instrument to $900.00.
Techniques have been developed to deter fraudulent alteration of financial instruments through this cut and paste scheme. One such technique is shown in Mowry, U.S. Pat. No. 4,733,887, Mowry, U.S. Pat. No. 4,749,213, and Mowry, U.S. Pat. No. Des. 304,458. In this very successful approach, a financial instrument has an amount printed on its face, with the digits making up the amount being printed by a dot matrix printer in a negative pattern. Each of the digits includes a boundary portion formed by a single row of dots which makes up a portion of the outline of the adjoining digit. The digits are designed to be of varying widths. Each of these features makes cut and paste alteration of the printed financial instrument more difficult. Additionally, other methods of document alteration are made more difficult by the fact that each digit has an open, unprinted area within which the name of the digit is printed in letters, and the dots defining each digit are arranged in rows which are spaced sufficiently to allow a portion of the underlying paper to be seen. Further, the shapes of the various digits are selected such that it is very difficult to alter one digit by additional printing to produce another, properly formed digit.
While this technique is quite effective with domestic money orders, it is not sufficient to prevent fraudulent alteration of financial instruments which can be made out in any of an number of national currencies. Due to exchange rates, if a document carrying an amount in one national currency were to be altered to reflect a different currency, the value of the document could be altered dramatically. Typically, international financial instruments, such as bank drafts, carry a three letter code, termed a multi-letter international monetary code, which indicates the national currency in which the amount is printed. By simply altering this three letter code, as by the cut and paste method described above or by other alteration techniques, it has been possible to fraudulently increase the amount of an international financial instrument.
Accordingly, there still exists a need in the art for an international financial instrument and method of preparation which make alteration of the monetary amount of the instrument difficult and readily detectable.